My 2 cents worth, since I'm considering the same sort of things: I'm new to the neighborhood and have been over to the one neighbor's a couple times this winter to help him move wooodchips for his little horse barn and have box bladed/filled some mid-winter thaw ruts for him. I've got a Kioti CK 25 & loader & BH and a tiller and box blade and landscape rake and I'm going to bet I'm the best thing my neighbor's seen move into the neighborhood lately!
That said, they're nice friendly folks who just don't happen to have a tractor yet (but probably will at some point) and I certainly don't mind helping out. They've always offered to help us. He's got a snowplow on his second truck and was almost put out when I told him he didn't need him to plow my driveway for me! But I've got the Kioti and a snowblower on a JD GT245 (and I drive a Toyota 4x4) so I'm not exactly in danger of getting snowed in.
I probably wouldn't charge him if he needed something but I did think I should get some "light tractor work" business cards printed up. With prices. That way I could pass them out to the neighbors and tell them to let their friends and relatives know. And if they want somethig done they'll expect to pay for it. And I can not charge them, or give them the reduced "neighbor" rate, at my discretion. I guess I'd rather either charge someone what I think a job's worth or do it for free, as opposed to doing it for "fuel or shear pins," just so it's my decision about what I do witih my toys and for how much.
As for prices, I wouldn't think $75 out of line at all to rototill a 50' x 75' garden that I could drive to, if it had been a garden previously. A new plot, not previously tilled, might be more. -WSJ
At the time it sounded like a good deal for a small acreage. I only had 15 acres.
